﻿// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Globalization;
using System.Reflection;

namespace System.Windows.Forms;

/// <summary>
///  TreeNodeConverter is a class that can be used to convert
///  TreeNode objects from one data type to another. Access this
///  class through the TypeDescriptor.
/// </summary>
public class TreeNodeConverter : TypeConverter
{
    /// <summary>
    ///  Gets a value indicating whether this converter can
    ///  convert an object to the given destination type using the context.
    /// </summary>
    public override bool CanConvertTo(ITypeDescriptorContext? context, Type? destinationType)
    {
        if (destinationType == typeof(InstanceDescriptor))
        {
            return true;
        }

        return base.CanConvertTo(context, destinationType);
    }

    /// <summary>
    ///  Converts the given object to another type. The most common types to convert
    ///  are to and from a string object. The default implementation will make a call
    ///  to ToString on the object if the object is valid and if the destination
    ///  type is string. If this cannot convert to the destination type, this will
    ///  throw a NotSupportedException.
    /// </summary>
    public override object? ConvertTo(ITypeDescriptorContext? context, CultureInfo? culture, object? value, Type destinationType)
    {
        ArgumentNullException.ThrowIfNull(destinationType);

        if (destinationType == typeof(InstanceDescriptor) && value is TreeNode node)
        {
            MemberInfo? info;
            object[]? args;

            if (node.ImageIndex == -1 || node.SelectedImageIndex == -1)
            {
                if (node.Nodes.Count == 0)
                {
                    info = typeof(TreeNode).GetConstructor([typeof(string)]);
                    args = [node.Text];
                }
                else
                {
                    info = typeof(TreeNode).GetConstructor([typeof(string), typeof(TreeNode[])]);

                    TreeNode[] nodesArray = new TreeNode[node.Nodes.Count];
                    node.Nodes.CopyTo(nodesArray, 0);

                    args = [node.Text, nodesArray];
                }
            }
            else
            {
                if (node.Nodes.Count == 0)
                {
                    info = typeof(TreeNode).GetConstructor(
                    [
                        typeof(string),
                        typeof(int),
                        typeof(int)
                    ]);
                    args =
                    [
                        node.Text,
                        node.ImageIndex,
                        node.SelectedImageIndex
                    ];
                }
                else
                {
                    info = typeof(TreeNode).GetConstructor(
                    [
                        typeof(string),
                        typeof(int),
                        typeof(int),
                        typeof(TreeNode[])
                    ]);

                    TreeNode[] nodesArray = new TreeNode[node.Nodes.Count];
                    node.Nodes.CopyTo(nodesArray, 0);

                    args =
                    [
                        node.Text,
                        node.ImageIndex,
                        node.SelectedImageIndex,
                        nodesArray
                    ];
                }
            }

            if (info is not null)
            {
                return new InstanceDescriptor(info, args, false);
            }
        }

        return base.ConvertTo(context, culture, value, destinationType);
    }
}
